Patent GB-700089-A (GB)
Title: Improvements in or relating to telecommunication exchange systems
IPC: H04Q3/00
Filed: 1950-01-16
Abstract: 700,089. Automatic exchange systems. STANDARD TELEPHONES & CABLES, Ltd. (Hertog, M. den), Jan. 12, 1951 [Jan. 16, 1950], No. 1096/50. Class 40 (4). In a system generally similar to that disclosed in Specification 700,088 the register-controllers have direct access to the common control circuits of the selectors over auxiliary connectors independent of the conversational connection, selection being controlled over these auxiliary connections. The individual horizontal magnet of a selector may be energized simultaneously with the vertical bar the switching time thus being reduced. Specification 698,802 also is referred to. The multi-switches employed differ from those of Specification 707,221 in that the vertical bars are controlled by a set of five code bar magnets instead of by 25 vertical magnets. Each code magnet operates a corresponding code bar so that 25 combinations are possible each serving to select one of the 25 pairs of vertical bars. Vertical and horizontal servomagnets like those of the above-mentioned Specification are provided. The proposed layout for a 10,000 line exchange is shown in Fig. 1. The common control circuit provided for each multi-switch is designated ESBO and each ESBO may be connected by an ESBO connector (EC) directly to a register-controller. The connectors EC are multi-switches of which the inlets are associated with the register-controllers, the outlets being multipled for all register-controllers to the ESBO circuits. A register-controller prior to controlling a selection receives information as to the ESBO circuit to which it requires to be connected to control the individual selector involved. The layout for larger exchanges where the number of ESBOs requires more than one connector EC is also discussed. Detailed description : Figs. 3, 4, 5A-5D. As shown in Figs. 5A, 5B a connection is established over wires C, D of the conversational train between the register-controller and the individual selector to which connection is assumed to be established. This selector is assumed to be that of Fig. 3 and to be a third group selector. The ESBO of the preceding selector will have signalled the register-controller to establish connection via an ESBO connector directly to this third group selector ESBO (Fig. 4). As soon as the relevant digit (the hundreds) has been registered relay Hsr (Fig. 5D) pulls up under control of the registering equipment (not shown) and operates Tgr, individual to the ESBO connector giving access to the wanted ESBO, which closes circuits over wires 1 and 9 (Fig. 5C) to this ESBO. One of the horizontal servo-magnets SHa or SHb (Fig. 5D) of the connector will have been energized and locked up in series with Lar, and relay Br is up. With Hsr and Lar operated one of the sources Pdl ... 10 corresponding to the hundreds digit is connected to gate RG1, RG2 (Fig. 5B). This source is normally at ground potential but in a time position characteristic of the hundreds digit it provides an impulse at + 16volts. The electronic scanning circuit in the grid circuit of AT1 (Fig. 4) is controlled by pulse sources Pal ... 5, Pb1 . . . 5, and Pc1 ... 4 having impulse lengths of 1, 5, and 1 time units respectively so that the 100 paths from the Pa gates to the grid of AT1 are enabled cyclically in turn. An additional group of pulses sources Pd1 . . . 11 having an impulse length of 1 time unit is used to mark the group to which each outlet of the multiswitch belongs, each test lead e1 (Fig. 3) being connected via a rectifier gate to the corresponding terminal A00 to 99 (Fig. 4) which is cross-connected as required to the relevant pulse source Pd1 . . . 11. The outlets of the switch are thus scanned in successive groups during a period of 1100 time units each free line reverting an impulse to AT1 in the relevant time position during the 100 time units during which its group is scanned. These impulses are repeated by AT1 over wire 1 to the grid of separating tube ST (Fig. 5B) which in turn repeats them to a comparator circuit. Only if such an impulse coincides with an impulse from the locally-connected Pd source will the wire CW (Fig. 5B) assume a relatively positive., potential whereby the small condenser connected to the grid of AT3 is charged. Connected to the other side of this condenser is a pulse source d3 which produces a short positive impulse at the beginning of each Pa time unit. Thus when the next d3 impulse is sent the grid of AT3 goes sufficiently positive for the tube to conduct and a short negative impulse is transmitted from its anode circuit to the grid of FT1. FT1 and FT2 which comprise a stable triggered pair change over, the anode potential of FT1 rising from - 36 V to + 24 V. so that a 60V impulse is transmitted to the grid of AT4 which repeats it to the cold cathode tubes Va-Ve. The source d2 connected to the grid of FT2 provides an impulse towards the end of Cach Pa time unit and thus restores the pair FT1, FT2. One tube in each group Va1 ... 5, Vb1 . . . 5 and Vc1 . . . 4 is ionized the combination characterizing the outlet which provided the impulse. Tube Vd is also fired thus influencing the potential on wire CW so that subsequent impulses are absorbed and do not affect tubes AT3, 4 ; FT1, 2. The anode relays corresponding to the fired tubes Va, Vb, Vc pull up and record the identity of the selected outlet. The operation of Fr (Fig. 5B) brings up Sir (Fig. 5C) and Tdr (Fig. 5B) and a test is then made over wire 9 to determine whether the ESBO is free for switch control purposes. If it is free + 24V over either D2 or E2 (Fig. 4) is extended to the electronic sequence test circuit (Fig. 5D) which is such that each register-controller can test only in its own characteristic time, a successful test reducing the potential on wire 9 to prevent a second register-controller from making a successful test. The three gates in the grid circuit of AT5 (Fig. 5D) are controlled by a selection of sources Pa1 ... 5, Pb1 . . . 5, Pc1 . . . 4 to enable the path in the characteristic time unit of the register-controller concerned. Triggering impulses from d3 are also applied to this grid so that the tube conducts in the time interval following that in which the gates pass an impulse. Triodes AT5 and AT6 with transformer GT1 operate as a blocking oscillator so that AT6 is triggered and tube VS is fired. The common test lead 9 is thus rendered ineffective for further tests. Relay Tr pulls up in series with VS and operates Dr or Er and Lr or Mr (Fig. 5C) to register the group of 25 outlets to which the wanted outlet belongs. Tcr (Fig. 5D) also comes up and completes circuits'over wires 3 to 7 for the operation of a combination of code bar magnets AM ... EM (Fig. 4) under control of the operated anode relays Aar ... Aer and Bar . . . Ber (Fig. 5B). The operating ground is extended via relay Cr (Fig. 4) and wire 8 to operate Hrr (Fig. 5C) which connects direct ground to wire 8, Cr remaining down. Relay Br (Fig. 5D) relapses whereupon the operated, cold cathode tubes and anode relays restore. The operated code bar magnets hold in series with Cr (Fig. 4) which pulls up bringing up Cgr (Fig. 5C) and Chr (Fig. 5B). This last relay energizes SVa or SVb (Fig. 4) under control of Lr or Mr (Fig. 5C) and the relevant vertical bar is lifted. It also connects ground to wire 5 or 6 to short-circuit Dr or Er (Fig. 4) according as Er or Dr (Fig. 5C) was operated. Cgr then releases connecting ground to the C wire to operate HM in the selector, which in turn brings up Hcr (Fig. 5B) and locks to ground on the E wire. The sequence test circuit is connected over wire 5 or 6 and back D3 or E3 (Fig. 4) to one of the make contacts, e.g. VBa1, of the operated vertical bar which is extended to the test lead of the selected outlet so that AT5 (Fig. 5D) again functions when free test potential is on this lead and the outlet is busied. The operation of Tr (Fig. 5D) also energizes horizontal servomagnet SHa or SHb (Fig. 4), according as Dr or Er (Fig. 4) is back, to effect switching through at the selector by moving the horizontal bar. Opening of contacts HB (Fig. 3) releases Hcr (Fig. 5B) which de-energizes the horizontal servomagnet and brings up Okr (Fig. 5C). Br (Fig. 5D) reoperates connecting + 24V to the comparator circuit to render it dependent on impulses from tube ST (Fig. 5B) exclusively whereby the class of outlet signal is received from a second scanning circuit connected to tube AT2 (Fig. 4). This circuit comprises two stages of gates controlled by sources Pa1 . . . 5 and Pb1 ... 5 to give 25 points each connected via separating rectifiers to two conductors respectively associated with a terminal in the groups 00 to 24 and 25 to 49. Each of these conductors includes two gates controlled by Pc1, 2 or Pc3, 4 and Pel ... 3. The sources Pe each give an impulse of one time unit duration and three time units period. The sources Pc and Pe are used to give six classes of signal each indicative of an ESBO connector and the twenty-five combinations of Pa, Pb sources in conjunction with two Pc, Pe combinations give 50 signals in each class indicative of the outlets of the ESBO connector. The particular ESBO to be used in controlling the next selection depends upon the particular outlet selected at the selector under consideration. For this purpose a terminal ECT (Fig. 4) individual for each group selector outlet is connected via one of the make contacts on the vertical bar to that one of the terminals 00 to 49 indicating the wanted ESBO connector outlet. A potential of + 24V is thus connected over D2 or E2 and E1 or D1 to the relevant terminal and the scanning circuit produces an impulse in a time unit characteristic of the ESBO connector outlet and of the class of outlet. This impulse is applied via wire 2 and tube ST (Fig. 5B) to AT3 arid results in the firing of one tube in each of the four sets Va . . . Vc, Ve. Relay Rlr (Fig. 5D) pulls up releasing Tcr (which disconnects